The thermistor is the temperature sensor. If it fails (sends a wildly incorrect resistance reading), the control board thinks the machine is overheating even when it’s cold.
Ensure the water tank is full and seated perfectly in its base. If you use an Aqua Filter , try removing it temporarily to see if the filter itself is causing a blockage.
For DIY users, this often involves opening the machine to ensure the NTC sensor wires haven't vibrated loose.
: If the code persists, run a descaling cycle to remove mineral deposits that might be blocking internal flow. JustAnswer Remove the Filter krups error code 09
Once inside, locate the thermoblock (the large aluminum block with heavy wires attached to it). Fixed directly to the side or top of this block is the NTC sensor, usually identifiable by two thin, brightly colored wires leading back to the main circuit board.
With the machine plugged in but off, press and hold the power button for 10 seconds. Some models reset this way.
A broken sensor or its connection to the control board is the primary cause of this error, as highlighted in multiple support forums. In short, your machine is essentially saying, "I've asked the water to heat up, but the sensor isn't confirming it's happening!" The thermistor is the temperature sensor
Disconnected spade terminals or detached solder pads at the sensor. Resolder detached pads or clean and reseat the connectors. Low to Medium
If cleaning and re-seating connections doesn't work, you may need to source specific parts from Krups or authorized retailers:
For a visual walkthrough on how to perform a hard reset and factory restore for various Krups models, you can watch this guide: How To Reset Krups Coffee Machine | Easy Steps Search Mastery YouTube• Sep 27, 2025 Professional Repair vs. Warranty If you use an Aqua Filter , try
Suggest some to keep your machine in top shape.
Resistance across heating element terminals reads open circuit. Replace the entire thermoblock assembly. 🔍 Understanding the Root Causes of Error 09
If the error immediately reappears, the issue is hardware-related and requires deeper inspection. Step 2: Advanced Hardware Diagnosis & DIY Repair
: The internal heating element inside the cast-aluminum assembly can develop an open circuit over years of thermal expansion and contraction, stopping all current flow. Step-by-Step Diagnostic and Repair Workflow
Heavy scale accumulation acts as a thermal barrier. It forces the heating element to run hotter and longer to reach brewing temperatures, drastically shortening the lifespan of both the NTC sensor and the thermal fuses. Use Krups-approved descaling powder every 2 to 3 months.